For the sauce vierge, dry-fry the coriander seeds in a hot frying pan until they release their aroma. Place them in a pestle and mortar and crush.
Peel the garlic clove and mash to a paste with the tip of a knife and some sea salt. Add the garlic paste to the pestle and mortar.
Add 2-3 tablespoons of extra virgin olive oil to the garlic and coriander and stir.
Remove the core and seeds of the tomato. Chop the flesh roughly and add to the pestle and mortar.
Roughly chop the herbs and add them to the pestle and mortar. Crush all the ingredients together well to form a sauce. Allow the flavours to infuse while you prepare the scallops.
Trim off any tough, sinewy flesh and remove any black veins from the scallops, but keep the roes intact.
Heat a frying pan or griddle pan until hot. Drizzle some olive oil over the scallops and season with salt and freshly ground black pepper.
Place the scallops on the hot pan or griddle and cook until they're just cooked through, about 2-3 minutes on each side, depending on size. They'll feel firm to the touch when cooked. (If the scallops are very large, you can finish them in a preheated oven for a few minutes.)
Finish the sauce vierge by adding the lemon juice (don't do this until just before serving or the herbs will turn black). Adjust seasoning and stir well.
To serve, spoon the sauce vierge over the scallops and garnish with the quartered lemons.